1. Field of the Invention
The present invention relates to a tap antenna unit which includes a signal wave splitter coupled to a television coaxial cable and having an output coupled to a filter, which can be a surface acoustic wave (SAW) filter capable of selecting a low-level but sharp frequency band somewhere in the energy spectrum of TV coaxial cable, such as for example 100-200 Khz wide, 40 dB down, located between 50-800 MHz. The signal is not carried in the video signal and is AM modulated with digital data at around 10 Kb per second and such digital data is remodulated onto a carrier signal in the unlicensed ISM band at 902-928 MHz, e.g. 916 MHz, and broadcast via a self-contained antenna to a receiving unit, such as a remote control.
Further, the present invention relates to a two-way tap antenna unit which can support two-way communication for devices in the home, such as a remote control, that can send 900 MHz data to the tap antenna. Such data is received by the tap antenna unit, demodulated, and then either remodulated onto the coaxial cable through a splitter/combiner at a frequency below 50 MHz, or provided at a connector as a baseband signal or sent through a processor or modem. In this way, equipment upstream from the tap antenna unit, or built into the tap antenna unit, can receive commands or data from devices in the home, such as a remote control.
2. Description of the Prior Art
Heretofore communication to a remote control has been through a telephone modem or from a cable box via IR signals. Further, it has been suggested to communicate with a remote control via radio signal. However, the use of a local transmitter or a local transceiver has not heretofore been proposed.
Also, heretofore the transmission of another signal within a video signal has been proposed. See the following U.S. Patents.
______________________________________ Patent No. Patentee ______________________________________ 4,807,031 Broughton et al. 4,920,503 Cook 5,200,822 Bronfin et al. 5,213,337 Sherman 5,251,301 Cook 5,539,471 Myhrvold et al. 5,572,247 Montgomery et al. 5,621,471 Kim et al. 5,655,945 Jani 5,666,293 Metz et al. 5,675,575 Wall, Jr. et al. 5,708,476 Myhrvold et al. ______________________________________